WordPress.org

Using FTP

* download the plugin to your local computer
* Extract the plugin archive
* ftp the entire livepress/ directory to your wordpress plugin directory
* Go to your WordPress Dashboard -> General -> Writing and make sure XML-RPC is enabled.
* Go to your plugins admin page and activate the LivePress plugin
* Go to the Settings -> LivePress to configure your plugin on the admin page 

Using shell access

* cd to your wp-contents/plugins directory of your wordpress installation
* download the plugin archive directly
* # wget http://downloads.wordpress.org/plugin/livepress.x.x.x.zip
* unzip the files
* unzip livepress.x.x.x.zip
* If you ran this as root, you may need to fix file ownerships
* chown -R <wpuser> livepress
* again, check file ownership
* Go to your WordPress Dashboard -> General -> Writing and make sure XML-RPC is enabled.
* Go to your plugins admin page and activate the LivePress plugin
* Go to the Settings -> LivePress to configure your plugin on the admin page 

Crossposting Text Via Email

* Configure wordpress to use email to post to the blog
(http://codex.wordpress.org/Post_to_your_blog_using_email)
* Configure the "Email Crossposting" section in the LP admin page

Crossposting Image/Video Via Email

* Follow instruction above, plus..
* Install and configure the PostMaster plugin. 
* LivePress will crosspost the entry to Livejournal along with the multimedia content.